// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_URL_REQUEST_URL_REQUEST_THROTTLER_ENTRY_INTERFACE_H_
#define NET_URL_REQUEST_URL_REQUEST_THROTTLER_ENTRY_INTERFACE_H_

#include <stdint.h>

#include <string>

#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/time/time.h"
#include "net/base/net_export.h"

namespace net {

class NetworkDelegate;
class URLRequest;
class URLRequestThrottlerHeaderInterface;

// Interface provided on entries of the URL request throttler manager.
class NET_EXPORT URLRequestThrottlerEntryInterface
    : public base::RefCountedThreadSafe<URLRequestThrottlerEntryInterface> {
public:
    URLRequestThrottlerEntryInterface() { }

    // Returns true when we have encountered server errors and are doing
    // exponential back-off, unless the request has load flags that mean
    // it is likely to be user-initiated.
    //
    // URLRequestHttpJob checks this method prior to every request; it
    // cancels requests if this method returns true.
    virtual bool ShouldRejectRequest(const URLRequest& request) const = 0;

    // Calculates a recommended sending time for the next request and reserves it.
    // The sending time is not earlier than the current exponential back-off
    // release time or |earliest_time|. Moreover, the previous results of
    // the method are taken into account, in order to make sure they are spread
    // properly over time.
    // Returns the recommended delay before sending the next request, in
    // milliseconds. The return value is always positive or 0.
    // Although it is not mandatory, respecting the value returned by this method
    // is helpful to avoid traffic overload.
    virtual int64_t ReserveSendingTimeForNextRequest(
        const base::TimeTicks& earliest_time)
        = 0;

    // Returns the time after which requests are allowed.
    virtual base::TimeTicks GetExponentialBackoffReleaseTime() const = 0;

    // This method needs to be called each time a response is received.
    virtual void UpdateWithResponse(int status_code) = 0;

    // Lets higher-level modules, that know how to parse particular response
    // bodies, notify of receiving malformed content for the given URL. This will
    // be handled by the throttler as if an HTTP 503 response had been received to
    // the request, i.e. it will count as a failure, unless the HTTP response code
    // indicated is already one of those that will be counted as an error.
    virtual void ReceivedContentWasMalformed(int response_code) = 0;

protected:
    friend class base::RefCountedThreadSafe<URLRequestThrottlerEntryInterface>;
    virtual ~URLRequestThrottlerEntryInterface() { }

private:
    friend class base::RefCounted<URLRequestThrottlerEntryInterface>;
    DISALLOW_COPY_AND_ASSIGN(URLRequestThrottlerEntryInterface);
};

} // namespace net

#endif // NET_URL_REQUEST_URL_REQUEST_THROTTLER_ENTRY_INTERFACE_H_
